Electric circuit breaker



May 19, 1953 R. N. Rows.' 2,639,347

A' ELECTRIC CIRCUIT BREAKER Filed Dec. 4, 1948 Inventor'. Raymond N. Rowe,

Has A toTTwey.

Patented May 19, 1953 UNITED STATES PATENT OFFICE ELECTRC CIRCUIT BREAKER Raymond N. Rowe, Plainville, Colin., ssigoi', by mesne assignments, to General Electric Company, a corporation of New Yo'rk Application December 4, 1921-8, Serial o. 63,5573

9 Claims.

My invention relates to the type of switch in which the circuit may be opened and closed manually, opened automatically upon an overload and reset manually.

The main object is to provide a compact forznof mechanism of the toggle type which is simple, reliable and inexpensive.

Another object is to provide a maximum contact pressure with a minimum latch pressure.

Another object is to provide a circuit breaker of the foregoing type which is simple in con'- struction and easy to assemble and calibrate.

Another object is to provide a circuit breaker in which the accuracy of calibration does not depend. on or vary with dimensional stability of the supporting frame or housing.

The drawing shows an enclosed switch in which Fig. l is a longitudinal sectional view through a housing and showing switch mechanism involving one form of my invention in its closed circuit position.

Fig. 2 is a plan View of the parts of Fig. 1, with the cover removed.

Fig. 3 is a View similar to Fig. 1 but with the switch parts in the automatically tripped posiion.

Fig. 4 is a longitudinal sectional view of the base of` the housing with the mechanism in the manually open circuit position.

The housing consists of an insulating base I with an insulating cover 8. The terminals S and I0 are secured to the base. The stationary contact I I is connected to terminal 9 and the4 movable switch contact I 2 is carried by the switch arm I3 which is hinged to the trip member I B and moves between the walls of the U-shaped frame I5.

.The trip member I6 of insulating material is pivoted at Il in the frame and supports one end of the switch arm I3 in the hinge bearing or pivot IB. Thebimetal latch arm I9 is secured at one end to the switch arm I3 near contact I2 and near its other end carries an adjustable stud 20 which coasts with the trip member IB and is connected to terminal I 0 by the flexible condoctor i4.

The manually operable lever ZI is pivotedat 22 in the frame and has a knob or handle 23. The springs 2li, 24 connect the end 25 of lever 2| with the lugs 2'8 on the switch arm I3 near the contact end I2. The springs thrust the switch member I3 against the trip member at one side of the pivot I1 'and thrust the latch member I8 against the trip member at the opposite side of the pivot II. In the normal on position, the over-center springs 24, 24 pull against the lever 2l `which is pivoted at 2 2 andY bias the handle of the lever against the shoulder v2'4I on the frame. The principal reacting forces of the springs are taken up by the switch arml bearing against the trip member vat I8 and Vin turn pressing against the hinge II in the frame. The springs tendkto rotate the trip member clockwise as viewed in the drawings but are opposed by the pressure of the trip member against the latch stud 2.

To open the circuit manually, the lever 2| is turned clockwise (as viewed in Fig. l). This carries the end 25 `of the lever and spring to the opposite left-hand side` of th center line passing through the points 22 n and 26 and snaps the switch arm and ,tripinember as a unit about the pivot Il' to the ""oii position, the lever 2I resting against the pin 28 on the trip member and the switch member resting against the :trame at 34 and the tip of arm I9 pressing against the trip member as shown in Fig. 4. Reversal of the actior'il closes the circuit.

yAsshown in Figs. i and 2, the pivot I8 lies on the right-hand sid'eA of the liney joining the spring cnnecticn lugs Y2t with the trip member 'pivot Il, i. e. on the side inthe circuit-closing direction. TheA portion of Vthe lswitch arm I3 lyingbetween the pivots 264 and I8, therefore, constitutes one arm of a toggle, the other arm being formed by the portion of the trip member Illying betweenthe pivots I7 and I l. This toggle is normally in compression due to the force of the springsZd, and1 is moreover normally in a slightly overl-'set condition, as shown in the drawings, since the knee pivot I8 is' on the right-hand side of the line joining pivots 26 and I'I.

p Upon the occurrence of excess' current through the breaker contacts, the bimetal arm I9 is warped in a direction away from the arm I3 by the heat developed by the passage of current therethrough. When fthe bimetal arm I9 has denecteusumcienuy, it uisengages the stud 2c from the' trip inlenfiber IS. 'lieentire horizontal coinponent thems'pifing 24 isV thenexerted upon the tripnieniber at the' `pivot I8. This causes the toggle fbrmed by members I3 and IB to collapse, the trip member I6 turning clockwise so that the lower end of the switcharm I3 shifts slightly toward the right lia-nd and thev switch arm moves downwzvirliA end'wise until the bracket 30 engages the eridof the' guide arn 3l yas shown in Fig. 3. ThisA guide arnil is Arloun'ted on a Xed pvot r32 on the side oftnespring 24 opposite the switch arm I 8 when the switch arm in the closed posii tion as siitiii Fig. 1. Thereafter the switch arm I3 carrying the movable contact l2 and the bimetal arm i9 is mounted on the guide arm and is rotated by the springs 24 about the pivot 32 to the fully tripped open position of Fig. 3, the switch arm being connected at its end by the bracket 3i! to the end of the guide arm 3| so as to be supported by the guide arm. The bracket 3@ provides for relative sliding movement between the end of the guide arm and the switch arm during manual operation of the circuit breaker.

The guide member 3l as described provides for movement of the lower ends of the operating springs 24 to positions a substantial distance to the right of the pivot I8 of the switch arm, as shown in Fig. l, while at the'same time providing for automatic opening. It will be observed that with the operating springs in the position of Fig. 1, a high contact pressure is obtained for a given spring force because of the relatively large component of the spring pressure toward the right hand.

This tripping action as described will occur regardless of whether the operating handle 23 is held in the closed position as shown in Fig. l. As the described opening action occurs, however, the springs 24 are carried across the pivot point 22 of the handle so that if the handle is manually restrained during tripping, it will immediately be moved clockwise to the mid-position as indicated in Fig. 3 upon its release thereafter. If the handle is not restrained, it will move to the mid-position as shown immediately upon trip- 13mg. Y

In the mid or tripped position of Fig. 3, the handle and operating lever 2l are biased in a clockwise direction by the springs 24 against the pin 28 carried by the trip member ll.

To reset or prepare the breaker for use after an automatic opening, the bimetal having cooled sufficiently, it is merely necessary to move the switch handle clockwise from the position of Fig. 3 to the position of Fig. 4. During this movement, the handle rotates trip member I6 in a clockwise direction by reason of the engagement of the lever 2l with the pin 28 until the latching portion of trip member I6 is returned to the position of Fig.` 4, i. e. moved past the latch stud 2l) so as to be secure thereby.

It will be seen that I-have provided an eX- tremely simple mechanism which furnishes all the desirable attributes of an automatic circuit breaker, i.v e. operates with a quick-make-andbreak or snap action, is trip-free (i. e. cannot be held closed on an overload), and is trip-indicating (i. e. handle goes to a mid-position on tripping). A

Moreover, by reason of the construction shown, the accuracy of calibration does not depend upon or vary with dimensional stability of the supporting frame or housing because calibrationis determined by adjusting the spacing between the tip of stud 20 and the end of arm I3 in relation to the trip member I6. It is, therefore, possible to calibrate the mechanism apart from the frame or housing by merely comparing these two parts such as by pre-assembling them with the aid of a supporting jig.

I claim:

1. A circuit breaker comprising a stationary contact, a pivotally mounted trip member, a switch member having a contact at one end movable to a closed circuit position into engagement with said stationary contact and having its other end pivotally mounted on said trip member on oneside of the pivot. of said trip member, latching means normally engaged to secure said switch member against pivotal movement relative to said trip member, a spring connected to said switch member for applying an endwise force pressing said switch member against said trip member, manual means for moving said spring to move the direction of its force from one side to the otherof the pivot of said trip member to effect movement of said switch member and said trip member as a unit about the pivot of said trip member between closed and open circuit positions, and means responsive to the current through said contacts for disengaging said latching means upon the occurrence of a predetermined high current thereby to provide for pivotal movement of said switch member relative to said trip member.

2. A circuit breaker comprising a stationary contact, a pivotally mounted trip member, a switch member having a contact at one end movable to a closed circuit position into engagement with said stationary contact and having its other end pivotally rmounted on said trip member onl one side of the pivot of said trip member, a latch arm having one end secured to said switch member and its other end in engagement with said trip member on the opposite side of said pivot thereby normally to secure said switch member against pivotal movement relative to said trip member, an operating member, a spring having its ends connected respectively to the movable end of said switch member and to said operating member for pressing said switch member and said latch arm against said trip member and upon movement of said operating member for moving said switch member and said trip member as a unit about the pivot of said trip member between closed and open circuit positions, and means responsive to the current through said contacts for causing said latch arm to disengage said trip member upon the occurrence of a predetermined high current thereby to provide for pivotal movement of said switch member relative to said trip member.

y3. A circuit breaker comprising a stationary contact, a pivotally mounted trip member, aswitch member having a contact at one end movable to a closed circuit position into engagement with said stationary contact and having its other end pivotally mounted on said trip member on Vone side of the pivot of said trip member, a bimetal latch arm having one end secured to said switch member adjacent its movable end and extending into engagement with said trip member on the opposite side of said pivot thereby normally to secure said switch member against pivotal movement relative to said trip member, a pivotally mounted operating lever, an over-center spring having its ends connected respectively to the movable end of said switch member and the end of said operating lever so that movement of said operating lever effects snap movement of said switch memberand said trip member as a unit about the pivot of said trip member between closed and open circuit positions, and connections for heating said bimetal arm in response to the current through said contacts to cause said bimetal arm to disengage said trip member upon the occurrence of a predetermined high current thereby to provide for pivotal movement of said switch member relative to said trip member.

4. A circuit breaker comprising a stationary contact, a pivotally mounted trip member, a switch member having a contact at one end movable a Glosed circuit position intoengagement with said stationary contact and having its other end pivotally mounted on said trip member on rone side of the pivot of said trip member, latching means normally engaged to secure said trip member against pivotal movement relative to said switch member, a spring connected at one end to said switch member for applying an endwise force pressing said switch member against said trip member, means for moving the other end of said spring to move the direction of its force from one side to the other of the pivot of said trip member thereby to move said switch member and said trip member as a unit about the pivot of said trip member between closed and open circuit positions, a guide arm having a pivot on the side of said spring force 4direction opposite said switch member when said switch member is in said closed circuit position, a connection between the movable end of said guide arm and said switch member for mounting said switch member on said guide arm upon en'clwise movement of said switch member, and means responsive to the current through said contacts for disengaging said latching means upon the occurrence of a predetermined high current whereupon said trip member turns on its pivot and said switch member moves endwise into mounting engagement with said guide arm for movement by said spring about the pivot of said guide arm to an open circuit position.

5. A circuit breaker comprising a stationary contact, a pivotally mounted trip member, a switch member having a contact at one end movable to a closed position into engagement with said stationary cntat and having its other end pivotally mounted on saidrtrip member on one side of the pivot of said trip member, a bimetal latch arm having one end secured to said switch member and its other end engaging said trip member on the opposite side of said pivot. a spring connected at one end to said switch member for applying an endwise force pressing said switch member against said trip member, means for moving the other end of said spring to move the direction of its force from one side to the other of the pivot of said trip member thereby to move said switch member and said trip member as aunit about the pivot of said trip memberbetween closed and open circuit positions, a guide arm having a pivot on the side of said spring force direction opposite said switch member when said switch member is in said closed circuit position, a connection "between the movable end of said guide arm and said switch member for mounting said switch member on said guide arm upon endwise movement of said switch member, and connections for heating said bimetal arm in response to the current through said contacts so as to cause said bimetal arm to disengage said trip member upon the occurrence of a predetermined high current whereupon said trip member turns on its pivot and said switch member moves endwise into mounting engagement with said guide arm for movement by said spring about the pivot of said guide arm to an open circuit position.

6. A circuit breaker comprising a stationary contact, a pivotally mounted trip member, a switch member having a contact at one end movable to a closed circuit position into engagement with said stationary contact and having its other end pivotally mounted on said trip member on one side of the pivot of said trip member, latching means normally engaged to secure said switch member against pivotal movement relative to said trip member, a spring connected to said switch member for applying an endwise force pressing said switch member against said trip member, manual means for moving said spring to move the direction of its force from one side to the other of the pivot of said trip member to eiect movement of said' switch member and said trip member as a unit about the pivot of said trip member between closed and open circuit positions', means responsive to the current through said contacts for disengaging said latching means upon the occurrence of a predetermined high current, a guide arm having a pivot on the side or said spring force direction opposite" said switch member when said switch member is in said closed circuit position, and a connection between said guide arm and said switch member providing for movement of said switch member relative to said guide arm during manual operation of said switch member but supporting said witch member on said guide arm upon disengagement of said latching means thereby to provide for movement of said switch member together with said guide arm by said spring to an operi circuit position.

7. A circuit breaker comprising a stationary contact, a pivotally mounted trip member, a switch member having a Contact at one end movable to a closed circuit position into engagement with said stationary Contact and having its other end pivotally mounted on said trip member on one side of the pivot of said trip member, a latch arm mounted on said switch member extending into engagement with said trip member on the opposite side of said pivot thereby normally to f secure said switch member against pivotal movement relative to said trip member, an elongated spring connected at one end to said switch member for applying an endwise force pressing said switch member and latch arm against said trip member, means for moving the other end of said spring from one side to the other of the pivot of said trip member to eiTect movement of said switch member and said trip member as a unit about the pivot of said trip member between closed and open circuit positions, means responsive to the current through said contacts for causing said latch arms to disengage said trip member upon the occurrence of a predetermined high current, a guide arm having a pivot on the side of said spring opposite said switch member when said switch member is in said closed circuit pcsition, and a connection between said guide arm and said switch member providing for movement of said switch member relative to said guide arm during manual operation of said switch member but supporting said switch member on said guide arm upon disengagement of said trip member by said latch arm thereby to provide for movement of said switch member together with said guide arm by said spring to an open circuit position.

8. A circuit breaker comprising a stationary contact, a pivotally mounted trip member, a switch member having a contact at one end movable to a closed circuit position into engagement with said stationary contact and having its other end pivotally mounted on said trip member on one side of the pivot of said trip member, a bimetal latch arm secured to said switch member and extending into engagement with said trip member on the opposite side of said pivot thereby normally to secure said switch member against pivotal movement relative to said trip member, an operating member, a spring having its ends connected respectively to said switch member and said operating member so that movement of said 'operating -member eiects movement of said switch member andsaid trip member as a unit about the pivot of said. trip member between closed and open circuit positions, connections for heating said bimetal arm in. response to the current through said. contacts so as to cause said arm to warp and disengage said trip member upon the occurrence of a predetermined high current, a guide arm having a pivot on the side of said spring opposite said switch member when said switch member is in said closed circuit position, and a loose connection between said guide arm and said switch member, said connection providing for movement of said switch member relative to said guide arm during manual operation of said switch member but supporting said switch member on said guide arm upon disengagement of said tripmember by said bimetal arm thereby to provide for movement of said switch member together with said guide arm by said spring to an open circuit position.

9. A circuit breaker comprising a stationar contact, a pivotally mounted trip member, a switch member having a contact at one end movable to a closed circuit positioninto engagement with said stationary Contact and having its other end pivotally mounted on said trip member on one side of the pivot of said trip member, a bimetal latch arm having one end secured to said switch member adjacent its movable end and extending into engagement with said trip member on the opposite side of said pivot thereby normally to secure said switch member against pivotal movement relative to said trip member, a pivotally mounted operating lever, an over-center spring having its ends connected respectively to the movable end of said switch member and the end of said operating lever for applying an 'endwise force pressing said switch member and bimetal arm against said trip member so that movement of said operating lever to move its end of said spring from one side to the other of the pivot of said trip member effects snap movement of said switch member and said trip member as a unit about the pivot of said trip member between closed and open circuit positions, connections for heating said bimetal arm in response to the current through said contacts so as to cause said arm to warp and disengage said trip member upon the occurrence of a predetermined high current, a guide arm having a pivot on the side of said spring opposite said switch member when said switch member is in said closed circuit position, and a sliding connection between the movable end of said guide arm and the movable end of said switch member, said connection providing for relative sliding movement between said ends during manual operation of said switch member but supporting said switch member on said guide arm upon disengagement of said trip member by said bimetal arm thereby to provide for movement of said switch member together with vsaid guide arm by said spring to an open circuit position.

RAYMOND N. ROWE.

References Cited yin the le of this patent UNITED STATES PATENTS Number Name Date 1,726,233 Krantz Aug. 27, 1929 2,102,545 Rowe De-c. 14, 1937 2,329,362 Swingle Sept. 14, 1943 2,447,652 Jennings Aug. 24, 1948 2,494,868 Geremia Jan. 17, 1950 2,551,397 Rowe May 1, 1951 

